This invention relates to a fastener removing method and apparatus for removing frozen, stuck or sealant anchored fasteners from aircraft assemblies.
Heretofore frozen, stuck or sealant anchored fasteners having recessed heads such as the so-called Phillips, Reed and Prince screws when sought to be removed by employing ordinary screwdrivers has resulted in gouging, mutilating and damaging the driver slot. Hitting the screw with a hard object to loosen the screw has met with only limited success and in any event was time consuming. Hammering or drilling operations on screws in order to remove them can cause damage and effect parts surrounding the screw.
A tapping and quick reverse tool is shown in French Patent No. 730,418. U.S. Pat. No. 3,422,910 shows apparatus for impacting and torquing a bolt. U.S. Pat. No. 3,861,250 shows vibration forces per se utilized in loosening a frozen workpiece such as a nut or bolt.
In contrast with the previous methods and techniques for removing frozen, stuck or sealant anchored fasteners, the present method for removing fasteners involves the utilization of a pulsating force applied along the longitudinal axis of the screw extracting tool to the head of the fastener while simultaneously torquing the fastener alternately and sequentially in counterclockwise and clockwise directions about its central axis until the resistance to removal due to the stuck condition has been reduced to permit removal of the screw by conventional screwdriver.